SOLUTION: solve by completing the square. 3x^2+12x-9=0

Question 170236: solve by completing the square. 3x^2+12x-9=0
Answer by Alan3354(69443) (Show Source): You can put this solution on YOUR website!
solve by completing the square. 3x^2+12x-9=0
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3x^2+12x-9=0
Divide by 3
x^2 + 4x - 3 = 0
x^2 + 4x = 3
(x+2)^2 = x^2+4x+4, so add 4
x^2 + 4x + 4 = 3+4
(x+2)^2 = 7
x+2 = +sqrt(7)
x+2 = -sqrt(7)
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x = -2+sqrt(7)
x = -2-sqrt(7)
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Just for grins:

Solved by pluggable solver: SOLVE quadratic equation (work shown, graph etc)

Quadratic equation (in our case ) has the following solutons:

For these solutions to exist, the discriminant should not be a negative number.

First, we need to compute the discriminant : .

Discriminant d=28 is greater than zero. That means that there are two solutions: .

Quadratic expression can be factored:

Again, the answer is: 0.645751311064591, -4.64575131106459. Here's your graph:

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